While the graphics are not the most modern, nevertheless they do a very good job to deliver the impression of the terrain, and rendering long distances, also the colour palette is very good, normal woodlands on a normal blue day, or fog and snow, can indeed look very natural. However, I admitted that the videos looks nice. But whether looks are what decide a good sim, I doubt. Falcon 4 has an engine that is 12 years old now. Lock-On looked better - but did not take the crown, due to other deficits. Same was true for Flanker 2 and 2.5. Blaze of War looks nice, no doubt, but it seems to be a shooter-type of game, with tanks instead of humanoid bots.
On the other hand, sights and scopes in SBP offer you views that are the most realistical and best ones you can get in any tank game - no matter whether NVG, thermal or WWII-style optical sights.
Check the plethora of screenshots in the SBP resources and then tell me that the graphics do not get the job properly done!
They cover 4 years of pics. Yes, the SBP cpould be made looking even better. But no, that does not mean that it leaves important things to be desired. And some functional things it does better than any other ground environment engine I know of.
My point simply is: in a sim (and in cosims), I put functionality over looks. Unreal looks great, too. But that doe snot make it a sim. SF looked nice sometimes, too. But I had problems with it when thinking of it as a sim. As an action game, it was okay.